Subject: Re: [stella] Technologies From: Greg Troutman <mor@xxxxxxx> Date: Thu, 20 Nov 1997 22:05:44 -0800 |
Robert A. Colbert wrote: > > >Dark Mage utilizes SC bank-switching, but does not use RAM. I've not > >been able to successfully use SC RAM at all yet. It always crashes. > > Check the source code for Stell-A-Sketch - there is a nifty little >routine I have in there to move a chunk of memory. Feel free to use >it, but be warned that moving a chunk of memory is time consuming :) Yeah, I'm already pretty familiar with that routine ;) The problem is not writing RAM access stuff, but re-writing all the *other* stuff I have that inadvertently causes the game to immediately go wonky as soon as I merely enable write in the control byte of my WAV file... I haven't had an overwhelming need to use RAM that has gotten me to the point where I spend the many excrutiating hours re-writing a lot very touchy code... The 12 character display in Dark Mage, for example uses a STA.W extended mode write to zero page for cycle timing purposes... RESCUE has a ton of that sort of thing. What I really need is more ROM ;) I know I can write bank-switching code for either the SC or a standard hardware decode, but I'd like to pack as much as I can into 4K before going that route. I still have mild hopes that a complete and slick version of RESCUE will fit... One 4K game that I've played a bit of recently that is very impressive, IMO, is Activision's Spider Fighter. That game puts a lot of single scanline, fast moving, animated stuff on screen without any flicker. The trick they use is to have one free-moving sprite teamed up with 4 pseudo-free-moving sprites that actually jiggle in horizontal ranges to give a high-speed illusion that 5 enemies are flying around freely. Some amazing code that I can't quite figure out, starting right at $F000, allows all that, plus bunch of missiles to fly as well... Very nice. I think I should be able to do a decent version of RESCUE in 4K considering that game as a sort of similar precedent. -- mor@xxxxxxx http://www.crl.com/~mor/ -- Stella list is Administered by krishna@xxxxxxxxxxxx <Glenn Saunders> Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/stella.html +-shameless plugs-------------------------------------------------------+ | Stella documentary at http://www.primenet.com/~krishna | | Nick's VCS links via http://www.primenet.com/~nickb/atariprg.htm | | Write the best game, win framed autographs of famous Atari alumni!! | +-----------------------------------------------------------------------+
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